System and Method for an Energy Efficient Network Adapter

ABSTRACT

In accordance with an embodiment, a network device includes a network controller and at least one network interface coupled to the network controller that includes at least one media access control (MAC) device configured to be coupled to at least one physical layer interface (PHY). The network controller may be configured to determine a network path comprising the at least one network interface that has a lowest power consumption of available media types coupled to the at least one PHY.

PRIORITY CLAIM TO PROVISIONAL APPLICATION

This patent application claims priority to U.S. Provisional ApplicationNo. 61/558,752 filed on Nov. 11, 2011, entitled “System and Method foran Energy Efficient Network Adaptor,” which application is herebyincorporated by reference herein in its entirety.

TECHNICAL FIELD

The present invention relates generally to networking systems, and moreparticularly to a system and method for an energy efficient networkadaptor.

BACKGROUND

As networked devices have become cheaper and more capable, the marketfor these devices has exploded. Further, users are demanding greaterspeeds, better performance, and seamless operation from these devices.User demand for better QoS and high network availability coupled withdevice interoperability is driving the development of devices withmultiple network interfaces, and standards for integrating multipleinterfaces into a single home area network. Proliferation of devices andnetwork interfaces means that power consumption of the network interfacebecomes an increasingly relevant concern for device owners andoperators.

Power consumption has several negative user-visible effects, some ofwhich include: it is a significant contributor to the long-term cost ofownership of a device; it reduces battery life and increases the costand complexity of the power supply; and it can raise device temperature,potentially increasing design size and complexity to accommodate morepowerful cooling mechanisms. Device power consumption can be reduced byreducing effective clock speed and by disabling components of the devicefor the period in which they are not in use. These techniques are moredifficult to apply to the networking layer of a given device, as designsoften assume that network requests will be unpredictable.

SUMMARY OF THE INVENTION

In accordance with an embodiment, a network device includes a networkcontroller and at least one network interface coupled to the networkcontroller that includes at least one media access control (MAC) deviceconfigured to be coupled to at least one physical layer interface (PHY).The network controller may be configured to determine a network pathcomprising the at least one network interface that has a lowest powerconsumption of available media types coupled to the at least one PHY.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the embodiments, and the advantagesthereof, reference is now made to the following descriptions taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram of a hybrid network system;

FIG. 2 illustrates a hardware block diagram of a hybrid network system;

FIGS. 3 a-b illustrate implementation examples of a hybrid networksystem;

FIGS. 4 a-b illustrate embodiment systems;

FIG. 5 illustrates an example Beacon period configuration for IEEE 1901;

FIG. 6 illustrates a conventional radio parameter negotiation process;

FIG. 7 illustrates an MPDU format and receive state diagram;

FIG. 8 illustrates a logical structure and corresponding MPDUs for alatency optimized transmission;

FIG. 9 illustrates a logical structure and corresponding MPDUs for anefficiency optimized transmission;

FIG. 10 illustrates a spectral plot showing the maximum per-frequencyenergy distribution of a transmission at a transmitter;

FIG. 11 illustrates a spectral plot showing an example energydistribution at a receiver;

FIG. 12 illustrates an embodiment channel estimation process withamplitude negotiation;

FIG. 13 illustrates a spectral plot of an adjusted transmit amplitudeaccording to an embodiment system;

FIG. 14 illustrates a plot of a received frequency energy distributionwith adjusted transmit amplitude according to an embodiment system;

FIG. 15 illustrates an example preamble waveform at the transmitter;

FIG. 16 illustrates a received preamble waveform using a slow gainadjustment;

FIG. 17 illustrates a received preamble waveform using a fast gainadjustment;

FIG. 18 illustrates a heat-map depicting the energy required to transmita volume of data as a function of frame length and encoding rate;

FIG. 19 illustrates an embodiment convergent network; and

FIG. 21 illustrates an embodiment state machine.

Corresponding numerals and symbols in different figures generally referto corresponding parts unless otherwise indicated. The figures are drawnto clearly illustrate the relevant aspects of the preferred embodimentsand are not necessarily drawn to scale. To more clearly illustratecertain embodiments, a letter indicating variations of the samestructure, material, or process step may follow a figure number.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the embodiments are discussed in detail below.It should be appreciated, however, that the present invention providesmany applicable inventive concepts that can be embodied in a widevariety of specific contexts. The specific embodiments discussed aremerely illustrative of specific ways to make and use the invention, anddo not limit the scope of the invention.

The present invention will be described with respect to embodiments inspecific contexts, for example, a system and method for an energyefficient network adaptor in a hybrid network. Embodiment systems andmethods, however, are not limited to hybrid networks, and can be appliedto other types of networking systems.

In embodiments, a hybrid network approach leveraging multiple MAC/PHYstacks, such as the emerging IEEE P1905.1 standard, may reduce powerconsumption, by allowing communications to proceed along lower powerpaths when possible, and by disabling supplemental communicationschannels when the user does not require additional network capacity.

In some embodiments, power optimization is performed such that reducingdevice functionality is reduced in such a way that QoS is notcompromised. In other words, some embodiment power optimization methodsinclude strategically reducing certain device capabilities when thesecertain capabilities are not required; increasing capability only whenrequired to do so, and only to the extent required; and, when the samefunction can be performed in multiple ways, choosing the most efficientmethod.

In some embodiments, power consumption optimization uses the followinginformation: when system clients will require some function from thesystem; the level at which system clients require that function to beperformed; the energy required to communicate those requirements anddata to relevant parts of the system; and how much time and energy ittakes to change the capability level of the system. Some embodimentpower consumption optimization processes comprise maintaining this setof information, developing the historical knowledge that may be analyzedto detect trends and patterns as an example, and of acting on it.

Generally, embodiments of the present invention involve scheduling andselecting data transmission paths in hybrid systems havingmultiple-network interfaces. For example, an IEEE standard currentlyunder development, “P1905.1—Standard for a Convergent Digital HomeNetwork for Heterogeneous Technologies,” will support a convergeddigital home network (CDHN). Some embodiments include an abstractionlayer for multi-network-interface devices operating in a home networkfor the purpose of providing a common data and control interface toheterogeneous network technologies including: Wi-Fi (IEEE 802.11x),Ethernet (IEEE 802.3), MoCA 1.1 and HomePlug AV 1.1. The abstractionlayer common interface allows applications and upper layer protocols tobe agnostic to the underlying home network technologies.

FIG. 1 illustrates an embodiment of the IEEE P1905.1 Draft Standardimplemented as an abstraction layer. Block diagram 100 shows theabstraction layer with unified Service Access Point (SAP) 102 performinga variety of functions in blocks 104 and 106 to achieve the convergence,abstraction, and unification of previously standalone SAPs specific toeach media, such as HomePlug 108, Wi-Fi 110 and MoCA 112. In alternativeembodiments of the present invention, hybrid network structure 100 mayinclude greater, fewer and/or different network types and functions.

FIG. 2 illustrates a hardware block diagram hybrid network system 200showing Turbo Media Independent Interface (TMII) 202 coupled to hybridnetwork controller 204 that outputs power line communication (PLC)signal 206 at one interface and a Wi-Fi signal 208 at another interface.In one embodiment, the Wi-Fi signal 208 is produced by 802.11 adaptor212 that is coupled to hybrid network controller 204 via PCIe interface210. It should be understood that the diagram of FIG. 2 depicts just oneexample of a hybrid network system. Other embodiment hybrid systems mayhave any number of network interfaces of various network interfacetypes. For example, this may include a standalone PLC Interface coupledto the controlled 204 via a PCIe interface coupled in the same fashionas block 212. Alternatively, a fully integrated device may beimplemented such that controller 204 also includes some or all of thefunctionality of adaptor 212.

Hybrid networks, such as IEEE P1905.1 may be used, for example, toprovide multipath data communication in which data is transmitted viamultiple network connections, as is illustrated in FIG. 3 a showingrouter 220 communicating with television 222 via HomePlug networkconnection 224 and a Wi-Fi network connection 226. Hybrid networksystems may also be used to extend range as shown in FIG. 3 b, in whichtablet computer 230 is coupled to router 232 via a series connection ofHomePlug network connection 234 and a Wi-Fi network connection 236. Inan embodiment, this series connection may be used in place of singleWi-Fi network connection 238. It should be appreciated that the networktypes and device types shown in FIGS. 1-3 are only specificrepresentative examples of the hybrid network configurations that may beused in embodiments of the present invention. Other configurations usingother different network types and connection topologies may be used.

FIG. 4 a illustrates an embodiment of adapter system 300. Data interface302 (that may also be a SAP) is coupled to controller 304 that isfurther coupled to network interfaces 306, 308 and 310. These networkinterfaces may comprise a number of different MAC and PHY blocks, orthey may comprise a single MAC block and the plurality of PHY blockscoupled to the MAC block. These blocks may also be a single device whichis dynamically adaptable as described in U.S. Pat. No. 7,440,443,entitled, “Coupling between power line and customer in power linecommunication system” and as described in 8,050,287, entitled,“Integrated universal network adapter,” which are hereby incorporatedwithin in their entirety. Controller 304 inputs and outputs data to andfrom the data interface and determines over which of network interfaces306, 308 and 310 to transmit and receive data based on power controloperation and other parameters including QoS, as well as methodsdescribed herein. Data may be sent and received over the various MAC/PHYblocks simultaneously to utilize multiple media types coupled to saidblocks, including such transmissions where packets are interleavedand/or repeated among multiple media types. In some embodiments, packetspresented to the various MAC/PHY blocks such as blocks 108, 110, and 112illustrated in FIG. 1 do not necessarily correspond to the packetspresented at the unified SAP layer 102, as they may undergo translationand re-packing.

In an embodiment, some of the MAC functions that traditionally reside inthe media specific MAC are aggregated into a unified MAC engineperforming said functions for multiple media types and furtherintegrated with a CDHN type of functionality. Typically a MAC performs alot of queuing and buffer management to deal with the QoS requirementsand traffic prioritization/shaping. In some embodiments, the MAC mayalso perform packet retransmission and reordering. In the case of asingle integrated engine performing both CDHN and multiple MACfunctions, the size of the required memory may be reduced due to areduction in the number of queues and buffers and sharing of theresources among multiple media specific interfaces. For example, in oneembodiment, MAC queues may be eliminated and CDHN queues may be used forall purposes. At the same time, a single instance of a CPU may managemultiple media specific MACs, thereby providing a reduction in cost andcomplexity.

In an embodiment, the controller may also determine the state of powersaving modes, such as clock frequency control, and power down states forvarious processing blocks and for the different MAC and PHY blocks. Insome cases, the controller may also schedule intervals of time duringwhich the network interface is not allowed to transmit or is scheduledto be powered down. The determination made by the controller may includedetermining which power saving strategies to use as well as issuingcommands and control signals to implement these power managementstrategies. Moreover, the determination of power management strategiesmay be made in various combinations in order to meet the requirements ofa particular user, or a particular type of network or network use casescenario. For example, if a content source is transmitting video andaudio to a playback device, the audio content may be transmitted over adifferent link from the video content. Because audio and video havedifferent bandwidth requirements, the links may be optimized furtherthan if they were transmitted in the same stream or were differentstreams over the same links.

FIG. 4 b illustrates adapter system 350 according to an alternativeembodiment. System 350 is similar to system 300 depicted in FIG. 4 awith the addition of MAC processing engine 352. In an embodiment, MACprocessing engine 352 may perform queuing functions among multiple mediaspecific MACs in the system. For example MAC processing engine 352 mayaggregate queuing functions that otherwise would be residing in mediaspecific MACs residing in MAC/PHY blocks 354, 356 and 358. Advantages ofsuch an embodiment include the ability to further reduce the size andcomplexity of a system implementation.

In an embodiment, MAC processing engine 352, performs MAC functions thatare common or similar among multiple media specific MACs in the system.As an example, it could aggregate all the queuing that otherwise wouldbe residing in media specific MACs with the queuing necessary for theabstraction layer into a single optimized engine that further allows toreduce the size and complexity of the whole implementation.

The systems shown in FIGS. 4 a-b may be implemented on a singleintegrated circuit, or may be implemented using multiple integratedcircuits, or other components known in the art. The controller may beimplemented using a microprocessor, microcontroller, custom logic, orother circuitry known in the art. In some embodiments, operation of thecontroller may be software programmable, implemented in hardware with orwithout being configurable and/or programmable, or combination of thetwo.

In some embodiments, power may be reduced in four domains: in a singlenetwork interface in a single device; in a single network interfaceacross all devices sharing that network; in multiple network interfacesin a single device; and in multiple network interfaces across the unionof the devices that can communicate using these networks. Accordingly,in some embodiments, power may be reduced: within a single MAC/PHYimplementation on a single device; within a single MAC/PHYimplementation across a whole network; across multiple MAC/PHYimplementations on a single device; and across multiple MAC/PHYimplementations across a whole network. While embodiments are describedherein with respect to IEEE 1901-2010™ standard (IEEE 1901) as anexample of a network MAC/PHY, and IEEE P1905.1 (as an example of ahybrid network), embodiments are broadly applicable beyond thesespecifically described contexts.

IEEE 1901 defines a MAC/PHY for PLC, including provision for TimeDivision Multiple Access (TDMA) and Carrier Sense Multiple Access (CSMA)modes for medium coordination. IEEE 1901 networks include a singlenetwork management node, called the BSS Manager, which provides a stableclock reference for other devices on the network, and which coordinatesthe allocation of TDMA and CSMA periods for device communications.

TDMA regions in IEEE 1901 are managed by the BSS Manager, andcommunicated to network stations through the Persistent andNonpersistent Schedule BENTRYs in network Beacons. To communicate in aTDMA region, a station must characterize the network traffic that couldoccur in a TDMA region in a Traffic Specification (TSPEC), and presentthis TSPEC to the BSS Manager in a TDMA allocation request. FIG. 5illustrates an example Beacon period configuration for IEEE 1901.

Diagram 500 illustrating a radio parameter negotiation is illustrated inFIG. 6. In IEEE 1901 networks, unicast communications parameters are theproduct of a negotiation between the source represented as Station A 502and destination represented as Station B 504. In the negotiationprocess, Station A 502 first sends a SOUND frame 506 to Station B 504.On receiving a SOUND frame, Station B 504 collects information aboutreceive fidelity for that frame from the PHY. This information is usedto calculate the radio configuration information (or “tone-map”) thatStation A 502 should use for future communications with Station B 504.Station B 504 responds to the SOUND frame with a SOUND_ACK 508,indicating whether or not Station A should send more SOUND frames 506before tone-maps can be returned to Station A 502. After enoughinformation is collected, Station B 504 will send aCM_CHAN_EST.indication message 510 to Station A 502. This messageincludes the set of tone-maps that Station A 502 should use for futuretransmissions to Station B 504.

Though the IEEE 1901 PHY is designed to be capable of up to 4096-QAMmodulation, a large percentage of the medium time will be of a form thatrequires much less transmitter and receiver accuracy. During suchperiods, the PHY clock may run at reduced rate, thereby saving power.

At times during which no station is transmitting (the medium is Idle),the PHY may only need sufficient accuracy to detect the beginning of aPriority Resolution Symbol (PRS) (during the PRS window) or a preamble.After detecting a PRS, the PHY need not receive any additional mediumsignals until the current PRS period ends. On the other hand, receivingpayload requires increasing receiver fidelity as the Mac Protocol DataUnit (MPDU) is processed: the beginning of the preamble may be detectedmore simply than the preamble-to-Frame Control boundary; and it issimpler to detect the end of the preamble than to decode the framecontrol or payload data. In an embodiment, the simpler parts of theMPDUs may potentially be transmitted and received at a reduced samplingfrequency, thereby saving power. For example, in an embodiment, initialpreamble detection (and PRS detection) may run at lower samplingfrequency than the preamble-boundary detection.

FIG. 7 illustrates MPDU format and receive state diagram 550. Thereceiver starts out searching for preamble state 560 while the trafficon the wire is idle. When the receiver receives preamble 552, thereceiver transitions to search for preamble end state 562. At thereception of Telecommunications Industry Association (TIA) Frame Control(FC) 554, the receiver transitions to a receive TIA FC 564 state untilthe reception of AV FC 566, in which case the receiver transitions toreceive AC FC state. These TIA FC messages comply with the standard“TIA/TR-30.1, TIA 1113: A Medium Speed (Up to 14 mbps) Power LineCommunications (PLC) Modem, May 2008” (TIA 1113), which is incorporatedherein in its entirety. Once payload frames 558 are received, thereceiver transitions to receive payload frame state 568. At theconclusion of the reception of payload frames 558, the receiver onceagain assumes search for preamble state 560.

Reducing the sampling clock rate may have a beneficial effect on powerconsumption; and disabling the receive logic entirely may have an evengreater positive effect. This entails identifying periods in which novalid data should be received. Such periods may be referred to as“Receiver Irrelevant Periods”, or RIPs.) Some RIPs are triviallyidentified (such as when the station itself is the transmitter, orduring inter-MPDU intervals), some will occur due to the staged natureof the receive operation, and others are dependent on individual stationproperties and the region-type in the Beacon period.

Some RIPs include the time between detection that the MPDU data on thewire is irrelevant to the receiver, and the expiration of the receiver'svirtual carrier sense timer for that MPDU. This may happen in at leasttwo ways: early stage receive-operations for the MPDU data can fail(preventing later stage receipt—e.g. failure to detect the end of apreamble can prevent frame control receipt, and frame control decodefailure can prevent payload receipt); or early stage MPDU data canindicate that the local receiver is not the intended recipient. Forexample, the destination terminal equipment identifier, or the shortnetwork identifier in an AV Start-of-Frame frame control may not matchthe local device's configuration. In either case, the frame isguaranteed not to be destined to the local device, and may be ignored insome embodiments of the present invention.

Other RIPs may be determined by the Beacon region allocation. Ingeneral, stations not participating in a particular global or local linkare not active on the medium during the TDMA regions allocated to theselinks. (An exception is the BSS manager or proxy BSS manager, whichneeds to listen to medium activity during TDMA regions, for accountingand maintenance purposes.) Stations do not generally need to listen tothe medium during Stayout or Protected regions, and only the BSS Managerwill generally need to listen to the medium during Beacon Regions forforeign networks.

As previously described, during Stayout or Protected regions, stationsneither transmit nor receive the network payload. As such, the rate ofpower consumption may be significantly reduced during these regions. TheIEEE 1901 BSS Manager station controls the overall structure of theBeacon region. FIG. 5 illustrates an example Beacon region configuration400 having Stayout regions 402 and 412, Beacon regions 404 and 414, CSMAregion 406 and TDM regions 408 and 410. By reducing the size of CSMAregion 406, and increasing the size of a Stayout region 402 or 412 theBSS Manager may reduce power consumption across every device in the IEEE1901 network.

Reducing the size of CSMA region 406 will reduce the available bandwidthfor the whole network, which may reduce user-perceived networkperformance. In an embodiment, this concern may be partially addressedby having the BSS manager observe medium utilization during the CSMAperiod. When usage drops below a certain threshold for a sufficientperiod of time, the BSS Manager might increase the duration of Stayoutregion 402 or 412 and decrease the duration of CSMA region 406. If theusage exceeds a different threshold for a sufficient period of time, theBSS manager may perform the reverse operation, making more timeavailable for network traffic during CSMA.

The tone-map used for communications may have some impact on the powerconsumption of the transmitter. For example, high-bandwidth tone-mapsmay require more power per active transmission time than a low-bandwidthtone-map, due to the larger amount of data processed. High-bandwidthtone-maps may also require less active transmission time on the mediumthan low-bandwidth tone-maps. As placing transmit data on the mediumrequires more energy than polling the medium for MPDUs to receive, thisimplies that, at the signal-generation level, higher-bandwidth tone-mapswill generally save energy over low-bandwidth tone-maps per unittransmitted data. When it is possible to choose from a set of tone-mapsfor transmission, embodiment power consumption may be reduced by usingthat tone-map that will result in: first, the lowest amount of energybeing placed on the medium; and second, the lowest energy required toencode the data. In practice, this will usually mean determining whichtone-maps will occupy the shortest period of time on the medium, andthen choosing the lowest-bandwidth tone-map from that set.

In an embodiment, reducing the energy in the transmitted signal may alsohelp in reducing power consumption in a device. While a uniformreduction in transmission amplitude likely decreases the signal-to-noiseratio (SNR) at the receiver, harming QoS, strategically reducing thetransmitter amplitude in specific frequency ranges can reduce the powerrequired to transmit an MPDU, and will not degrade—and may evenimprove—receiver performance in some embodiments. An embodimenttransmitter may exploit this opportunity by reducing the transmitamplitude on inactive frequencies in the tone-map. This may be improvedfurther, by modifying the tone-map negotiation process at the IEEE 1901network level. Such a technique is described below.

Any IEEE 1901 Long MPDU requires communications overhead beyond what isstrictly necessary for communicating payload: it includes an MPDUheader; transmission of the MPDU may introduce padding into the framestream; and a receiver will usually be expected to transmit a responseMPDU. Therefore, reducing the number of MPDUs required for a givenvolume of payload may improve the efficiency of the IEEE 1901 network.In some cases, a station will be able to determine that data availablefor transmission is not immediately required by the destination. In sucha case, the station may defer transmission until either the recipientrequires the data, or enough data has accumulated so that the outboundtransmissions would be optimally efficient.

FIG. 8 illustrates logical structure 600 and corresponding MPDUs 601 fora latency optimized transmission. In logical structure 600, MSDUs 602,606 and 608 are mapped into PHY blocks 612, 614, 616 and 618 along withPad regions 604 and 610, such that Pad region 604 extends to the end ofPHY block 614. In the resulting MPDUs PHY blocks 612 and 614 followheader 620, and PHY blocks 616 and 618 follow header 624 separated byresponse block 622.

FIG. 9 illustrates a logical structure 630 and corresponding MPDUs 631for an efficiency optimized transmission. In logical structure 630,MSDUs 602, 606 and 608 are mapped into PHY blocks 612, 614 and 616 alongwith Pad regions 632, such that Pad region 632 extends to the end of PHYblock 616. In the resulting MPDUs PHY blocks 612, 614 and 616 followheader 634, followed by response block 622.

All TDMA regions have an expected traffic pattern (where the trafficpattern includes such aspects as expected medium usage, the twocommunications endpoints). Within a TDMA region, the receiving stationwill always know the identity of the transmitting station. As such, thereceiver may improve its fidelity and decrease its activity bypre-configuring the radio to receive from this specific transmitter. Forexample, the signal quality from the transmitter to the receiver is notlikely to change very frequently; the receiver can rely on this topre-program the gain it expects to apply for this transmitter, prior tothe transmitter sending any payload on the wire. This will simplify thedynamic receive behavior, improving performance while slightly reducingpower consumption.

In embodiments of the present invention, various embodiment techniquesmay be used that may improve power consumption at the network level. Insome embodiments, these improvements involve coordination betweenmultiple devices, and enhancements may be made to the IEEE 1901 protocolto achieve these enhancements. It should be further understood thatsimilar embodiment enhancements may also be to other systems andprotocols.

A given IEEE 1901 station will generally use constant amplitude for allof its transmissions. This means that the transmitter will be perceivedas louder or quieter to different receivers, depending on signalattenuation along the path from the transmitter. For any given receiver,the signal attenuation generally will not be uniform across allfrequencies: some frequency ranges will show more attenuation thanothers. For example, FIG. 10 illustrates a power spectral density plotshowing the maximum per-frequency energy that can be transmitted, whileFIG. 11 illustrates a power spectral density plot showing an exampleenergy distribution at a receiver for that transmission. In thisexample, all frequencies show at least 15 db of attenuation at thereceiver, and there is a null around 24 MHz.

Receivers normalize the transmission by applying a gain to the receivedsignal, so that the ADC from the AFE will present the maximum possiblerange, while avoiding clipping. This generally improves receiveraccuracy, making higher-bandwidth modulations available to thetransmitter. However, the gain is generally applied in a uniform manneracross all frequencies. This means that receivers will usually seeimproved accuracy in less-attenuated frequency ranges, and less accuracyin more-attenuated frequency ranges.

FIG. 12 illustrates embodiment channel estimation process 700 withamplitude negotiation. Here the receiver response may be improved, andthe transmitter may emit less energy on the medium, by includingtransmit amplitude negotiation in the channel estimation process. Thereceiver represented by Station B 504 detects the energy levels atdifferent channels in SOUND frame 506, and forwards this information tothe transmitter in a new Management Message Entry (MME), which is calledCHES_AMP_MAP.indication 710. The transmitter, represented by Station A502, on receiving this MME, may adjust its amplitude map in such a waythat the receiver observes a flatter energy distribution acrossfrequencies by increasing the gain-adjusted usability of channels thathad previously been relatively faint. A power spectral density plot ofan adjusted transmit amplitude is illustrated in FIG. 13, and a powerspectral density plot of a resulting receive frequency energydistribution with adjusted transmit amplitude is shown in FIG. 14.

This process trades off a lower SNR for an improvement in the digitaloutput resolution of lower-energy carriers. In an embodiment, to ensurethat the transmitter has enough information to make the appropriatetradeoff, the CHES_AMP_MAP.indication 710 MME may also include collectedper-frequency SNR data.

IEEE 1901 receivers use the preamble to identify the start of modulatedpayload, and to determine the gain value that should be applied to thereceived signal after the preamble is detected. The amount of time thistakes may vary, depending on the gain adjustment technique used, and onthe amplitude of the signal at the receiver. In general, the larger thedifference between the gain setting when the medium is idle and thetarget gain setting for the receive operation, the longer the time itwill take for the gain to reach its target value. If the gain does notreach a target value early enough in the receive operation, datademodulation may be compromised in some cases.

FIG. 15 shows an example preamble waveform at the transmitter. FIG. 16illustrates the received preamble waveform using a slow gain adjustmentat a first receiver designated as “Station A,” and FIG. 17 illustratedthe received preamble waveform using a fast gain adjustment at a secondreceiver designated as “Station B.” At the beginning of both FIGS. 16and 17, both Stations A and B have the gain at maximum value while thereis no signal on the medium. In an embodiment, this facilitates receivingthe faintest possible MPDU. Station B hears the preamble much morefaintly than does Station A, so it takes less time to adjust its gain tothe target value. This means that the Station B may use more of thepreamble than can Station A, and that some of this extra preamble datamay be unnecessary for decoding the data. Had the transmitter beenissuing a unicast transmission to Station B, and had it sent a shortenedpreamble, less energy would have been placed on the medium, and StationB would still be able to decode the transmission. In an embodiment, areceiver measures the amount of time spent adjusting its gain, andreports this time to the transmitter as part of aCM_CHAN_EST.indication. The transmitter may then use this information toshorten outbound preambles for the destination.

The amount of energy it takes to communicate a MPDU in an IEEE 1901network may be expressed as follows:

E _(MPDU) =E _(sym) N _(sym) +K _(MPDU)  (1)

where E_(MPDU) is the amount of energy it takes to communicate the MPDU;E_(sym) is the amount of energy required to communicate each datasymbol; N_(sym) is the number of data symbols to be transmitted; andK_(MPDU) is some constant amount of energy for communicating thenon-varying parts of the MPDU. Both E_(sym) and N_(sym) are influencedby the radio parameters used to transmit the payload. Data modulatedusing a low-bandwidth tone-map may be encoded and decoded with a lowerPHY sampling rate, and may be reliably transmitted at lower amplitude,than can data modulated with a high-bandwidth tone-map. Assuming thatthe energy required to transmit a data symbol is proportional to thedata encoding rate, the amount of energy it takes to transmit a datasymbol may be expressed as:

E _(sym) =K _(sym) R,  (2)

where R is the data encoding rate. On the other hand, data transmittedat lower data encoding rate will generally require more data symbols fortransmission:

$\begin{matrix}{N_{sym} = {{{ceil}\left( \frac{8\left( {L + 8} \right)}{R} \right)}.}} & (3)\end{matrix}$

Expanding Equation (1) with the formulae for E_(sym) and N_(sym), thefollowing formula is obtained for calculating the energy required totransmit a MPDU based on the frame length and data encoding rate:

$\begin{matrix}{E_{MPDU} = {{K_{sym}{R \cdot {{ceil}\left( \frac{8\left( {L + 8} \right)}{R} \right)}}} + {K_{MPDU}.}}} & (4)\end{matrix}$

FIG. 18 Error? Reference source not found. illustrates a heat mapdepicting the energy required to transmit a volume of data as a functionof frame length and encoding rate. As can be seen, for any given framelength, the encoding rate may have a significant effect on the amount ofenergy it takes to transmit a frame, particularly at high data rates.While the nature of this relationship is dependent on the formula forE_(sym), which will be transmitter-, receiver-, and (potentially)environment-dependent, it may be the case that, for some trafficvolumes, energy may be saved by reducing the tone-map bandwidth.

This embodiment optimization may be supported by modifying the IEEE 1901channel estimation process to generate and communicate a set of relatedtone-maps. In an embodiment, each tone-map in the set is optimized formaximum energy efficiency with a given volume of traffic—fromhigh-volume/high-bandwidth encoding down to low-volume/low-energy. Thepayload receiver may take advantage of the fact that each tone-map inthe set is derived from the same channel radio characteristics toefficiently encode the tone-map set for communication to thetransmitter: the highest-capacity tone-map may use a current IEEE 1901tone-map encoding mechanism, while lower-capacity tone-maps may becommunicated as deltas from the next-higher capacity tone-map. When thetone-map set is synchronized between the transmitter and the receiver,the transmitter may select the optimal tone-map to use for sendingpayload across the medium, thereby saving power.

The above-described embodiment techniques may work better in TDMAregions than in CSMA regions. IEEE 1901 uses a CSMA/CA protocol tomanage the shared medium, and CSMA/CA relies on all network nodes beingable to detect when other nodes are communicating to avoid collisions.The above-described embodiment techniques may reduce the likelihood thatuninvolved nodes will be able to reliably detect communications. In someembodiments, the above-mentioned techniques may be further refined toreduce the probability of collisions and the prospect of decreasednetwork performance.

In an embodiment, the IEEE 1901 RTS/CTS protocol may be used to addressthis problem in CSMA regions. In one embodiment, during the RTS/CTSexchange, embodiment power reduction techniques are not employed: theRTS and CTS MPDUs are transmitted with standard transmit amplitude andwith a full-length preamble. Since other stations should be able toreceive the RTS and CTS MPDUs, the CSMA/CA algorithm may be much morerobust in this embodiment. After a successful RTS/CTS, the payload MPDUtransmission may use embodiment power reduction techniques relateddescribed above. In some embodiments, use of RTS/CTS means that theremay be some additional communications overhead, increasing powerconsumption, increasing latency, and decreasing bandwidth. In someembodiments, a determination is made if the power savings in the payloadcommunications will compensate for the expense of using the RTS/CTSprotocol. This determination may be a part of the algorithm executedeither by a single station or system wide collaboration where two ormore nodes participate in the analysis.

FIG. 19 illustrates convergent network 800 that may be defined as anetwork in which each node 802 and 804 may communicate using multipleMAC/PHYs 810, 812 and 814 coupled to different media 820, 824 and 826simultaneously. In an embodiment, each node has application layer 806and hybrid convergence layer 808. Each node also has a plurality ofMAC/PHYs represented by IEEE 1901 interface 810 coupled to IEEE 1901medium 820, Wi-Fi interface 812 coupled to Wi-Fi medium 824 and MoCAinterface 814 coupled to MoCA medium 826. It should be understood thatnetwork 800 illustrated in FIG. 19 is one example of many possibleembodiment networks. Alternative embodiment networks may include, forexample, greater or fewer MAC/PHY interfaces utilizing the same ordifferent network types.

The P1905.1 specification allows devices to communicate along multipleunderlying technologies at once. For any given P1905.1 station, it ispossible that some set of its underlying network interfaces are eitherunconnected (i.e. no other device can be reached using that interface)or redundant (i.e. no nodes can be reached using this network interfacethat can't also be reached using another). Unconnected networkinterfaces may be disabled to reduce power consumption. Such aninterface may be enabled, however, when attempting to discover otherdevices that might be reachable only using that interface. Discoverytime will be some fraction of the device's total uptime. Redundantinterfaces can potentially be disabled, but this is a delicate operationthat, implemented poorly, can prevent inter-device communications.

Disabling a redundant interface may reduce the availablecommunications-path redundancy in the network. Safely disabling aredundant interface involves ensuring that neighbor nodes do not disableall alternative paths to reach the local node. For example, consider thenetwork in FIG. 20, which depicts two stations connected by twointerfaces. Both interfaces INTERFACE1 and INTERFACE2 are redundant, soboth stations might choose to disable either interface. In this case, ifstation 1 disables INTERFACE1, while station 2 disables INTERFACE2, thenthe stations will no longer be able to communicate in some embodiments.

FIG. 21 illustrates embodiment state machine 900 that implements a safemeans of powering down a redundant interface. The state machinedescribes the enable/disable status of a network interface. Using thismachine, disabling an active network interface involves sending aSAFE_POWERDOWN command to the control plane of the interface. Theinterface responds to this command by issuing a topology update to allremote devices in the network on alternative interfaces. If all remotedevices acknowledge the topology update before a timeout expires, thenit will be safe to shut down this interface. Otherwise, the operationwill fail, and topology update messages are sent on all other interfacesto indicate that this network interface is still active.

In an embodiment, state machine 900 starts out in Idle state 902 andtransitions to Active state 904 on receipt of an ACTIVATE command. Atthe receipt of a SAFE_POWERDOWN command, state machine 900 transitionsto PowerDown_Start state 906. If an acknowledgement is received from allremote devices, state machine 900 transitions back to Idle state 902.Otherwise, state machine 900 re-enters Active state 904.

In an embodiment, disabling a redundant interface may save energy on thedevice. However, some interfaces are likely to draw more power thanothers. Disabling these high-power interfaces will result in greaterpower savings. Disabling a redundant interface will also reduce adevice's available communications capacity. In order to preserve QoS,such interfaces are re-enabled when more bandwidth is required forcommunicating to one of the stations reachable using that interface insome embodiments.

Streaming media applications are often characterized by communicationsof a large volume of media data, in which all media data is availablefor download immediately (limited by the bandwidth available between themedia host and the rendering device), but where rendering occurs overtime. In such applications, it will often be the case that a significantvolume of data is available for rendering, well ahead of the time atwhich that data will be rendered. The large period of time between whenthe data enters the network and when the application requires it createsan opportunity to optimize network power consumption by manipulatingtransmission timing, and the transmission path. Optimizing thetransmission path may use network-level information, and will bedescribed below.

Depending on the environmental circumstances, it can take more or lessenergy to transmit the same volume of data across a network link. Forexample, if a user runs a microwave, this may interfere with Wi-Fitraffic, such that any attempt to communicate during this interval willrequire significantly more power to be successful. If a user runs avacuum cleaner, this may interfere with IEEE 1901 traffic, meaning thatcommunications will consume significantly more power for the same volumeof data. A P1905.1 device may detect when there is a sudden decrease incommunications efficiency, for example, by measuring the transmissionsuccess rate as determined by MAC-level acknowledgements. (As thesuccess rate declines, so does communications efficiency). A P1905.1device may avoid transmissions while the medium is uncharacteristicallyinefficient, or until the user application requires the data. By usingembodiment methods to avoid communications while communicationsoperations are relatively inefficient, overall energy efficiency may beimproved.

Convergent networks are characterized by the existence of multiple mediaconnecting network stations (see FIG. 19). This implies that there willusually be multiple available communication paths between any twostations in the convergent network, and each such path will have anindependent power consumption profile. Choosing the most power-efficientpath requires information about the power efficiency of the paths underconsideration.

The power consumed for communications depends on several factors,including: the power required keeping a network interface active; thepower required to place a signal on the medium; and medium link quality.Each of these factors is itself a function of the underlying networkinterface technology, and of the physical network topology. As the IEEEP1905.1 network topology concept incorporates both the networkinterfaces available to a single device, as well as the availabledevice-to-device links along those interfaces, the IEEE P1905.1 topologytable is a natural place to store these power consumption data. Tofacilitate this, the IEEE P1905.1 topology query messages may beexpanded, in an embodiment, to include information such as:

TABLE 1 Expanded IEEE P1905.1 topology query messages Category DataInterpretation Network Startup Power required to bring the networkinterface Interface Cost from a powered-off state to a powered-on state.Network Shutdown Power required to bring the network interface InterfaceCost from a powered-on state to a powered-off state. Network RunningPower required to keep the network interface Interface Cost available tosend and receive traffic. Network Transmit Power required to send a unitof data to this Interface and Cost destination across this networkinterface. Destination Network Data Rate The data rate this stationwould achieve Interface and sending data directly to this destinationDestination across this network interface.

If any of this power-consumption information changes (e.g. due to a newinterference source making transmissions to a destination moreexpensive), this may be considered a change in network topology, and maybe communicated using the P1905.1 topology update mechanism in someembodiments.

In an embodiment, if the network topology table has been augmented withpower consumption information, then this information may be used todetermine the most power-efficient path to use for data communications.In this case, a weighted routing algorithm, such as Dijkstra'salgorithm, may be used to traverse the topology table to find the mostpower-efficient path from the data ingress station to the data egressstation that can support the required traffic load. Dijkstra's algorithmis described in E W Dijkstra, “A Note on Two Problems in Connexion withGraphs,” Numerische Mathematik, Vol. 1, pp. 269-271, 1959, which isincorporated herein by reference in its entirety.

In an embodiment, if the resulting path consists of a single hop, thenthe traffic may be directly sent to the destination. On the other hand,if the path consists of multiple hops, there are at least two availablerouting strategies: the origin may configure each station along the pathwith a routing rule, directing each node to forward data from this datastream along the subsequent edge in the communications path; or theorigin may forward the data stream to the next station in the path, andthe next station can use its topology table to determine the station itshould forward the packet to along the same path. In some embodiments,the second mechanism may be more robust if there is a sudden change innetwork topology. This, however, may lead to routing loops if the localtopology tables are not synchronized between the different nodes in thepath.

Another embodiment approach to conserving power is to attack the problemfrom the other direction: instead of considering how to reduce powerconsumption while leaving other aspects of network performanceunchanged, one may take power consumption as the constraint, andconsider how to achieve maximum network performance while not allowingpower consumption to exceed a user-specified envelope. In this case,embodiment techniques described herein may be applied with somemodification, and may result in increasing available communicationscapacity without increasing power consumption.

In an embodiment, power is reduced by using two user-specifiedparameters: maximum power consumption, and time interval. Availablepower is reduced as it is needed for communications, and increased astime passes. If available power gets too low, communications techniquescan become more conservative. In this way, communications will bepossible, but performance will degrade as power consumption approachesthe user-defined limit.

In a networking context, the term “Quality of Service” (QoS) is intendedto capture all user-visible aspects of network performance. Commercialattempts to improve QoS have a strong tendency to focus on those aspectsof QoS where users are the least satisfied—i.e. where the market demandis strongest. As networking technology becomes less expensive and morecapable, many new types of networked applications may becomeeconomically viable. For some of these applications, high powerconsumption may significantly degrade the user experience, as when asmartphone's battery is drained too quickly, or when a tablet device orlaptop becomes hot to the touch. Power consumption is becoming anincreasingly relevant aspect of QoS in fast-growing market segments.

In some embodiments, applying any given technique individually may leadto some improved efficiency. In some cases, greater efficiency may begained by applying multiple embodiment techniques at once. For example,automatically setting the receive gain during TDMA intervals will enablethe transmitter to communicate using much shorter preambles than wouldbe possible if the receiver had to spend time adjusting thegain—combining the TDMA fixed gain with the ability to shorten thetransmitted preamble may yield better efficiency than would applyingeach technique in isolation.

In an embodiment CDHN, common setup procedures may be used for addingdevices to a network, establishing secure links, implementing QoS, andmanaging the network. When a link goes down temporarily or is congested,an alternative route may be available to maintain data transmission.Furthermore, throughput may be aggregated and/or maximized via themultiple interfaces of a CDHN. These multiple interfaces may even allowfor multiple simultaneous streams. With applications such as interactiveTV, even a single person may be watching multiple streamssimultaneously.

CDHNs such as IEEE P1905.1 may also support traffic load balancing inwhich, for example, intelligently distributed multiple video streams areintelligently distributed over different paths to limit congestion onany single media and maintain reliability. Quality of service (QoS) mayalso be supported via prioritization over multiple technologies. IEEEP1905.1 may also allow devices to be configured in the same manner, forexample, with a simple button push. An IEEE P1905.1 hybrid network mayalso support advanced diagnostics in which the overall network monitorsitself. Moreover, an IEEE P1905.1 hybrid network may also supportmobility via wireless connectivity (mobile handsets, and tablets) anduniversal connectivity. For example, CDHN/IEEE P1905.1 may support ahybrid network in which one may connect to the hybrid network from everyroom in the house without having to be aware of which part of thenetwork and what media their device is currently interfacing.

At the same time, the proliferation of User Generated Content (UGC), theshift to Over The Top (OTT) delivery, and the explosive growth in thenumber of nomadic and stationary content rendering points, hasdramatically increased the importance of the networking layer to devicefunction: users demand reliable, QoS-aware networking platforms. Thereare at least two complementary approaches to meeting this market need:one can work to improve the performance of a given network interface,such as a MAC/PHY; and one can attempt to leverage multiple types ofmedia for link-level communications, as in IEEE P1905.1 hybrid networks.

Higher performance within a single network MAC/PHY may lead to increasedpower consumption. For example, communicating across a wider frequencyband may need more signal energy on the medium; more advanced FECtechniques may need more complicated circuitry to implement the morecomplicated algorithms; and MIMO techniques may need multiple instancesof certain parts of the PHY layer to run in parallel for a giventransceiver operation. Each of these techniques may increase the powerconsumption of the system.

In an embodiment, metrics, such as energy and traffic metrics are usedto determine lower energy ways to communicate from one device to atleast one other device over at least one media type. Embodiments mayapply intelligent means to proactively and dynamically adjust theparameters of the devices and selected communications networks in orderto minimize the amount of energy used to communicate. In someembodiments, energy is reduced while the user's expected quality ofservice is maintained.

In one embodiment, for example, in a simple network, embodiments systemsand method use information, for example, about the devices ability tomanage power, the ability to reduce the transmission power to theminimum level necessary for a particular application, and knowledgeabout which protocols to use (e.g. with or without security, orretries).

In a multi-protocol and hybrid media network embodiment, embodimentpower reduction techniques offers greater benefits because the networknodes may have the option of using multiple paths ormultiple-contemporaneous paths to get the data delivered from one nodeto at least another node.

Embodiment systems may involve a single MAC/PHY implementation on asingle device, a single MAC/PHY implementation on multiple devicesacross a whole network, a single device across multiple MAC/PHYinterfaces coupled to different media types, and/or multiple devicesacross multiple MAC/PHY interfaces coupled to different media typesacross a whole network.

In an embodiment integrated network adapter, a best path though thenetwork is dynamically selected based on the lowest power consumption ofthe available media types that can support the traffic. Thedetermination of power consumption may include the dynamic reduction ofa PHY output power based on a receiver's channel conditions based onquality parameters including AGC (Automatic Gain Control), SNR, and QoS(tolerance to losing packets).

In an embodiment, unused media interfaces, functions or components areturned off or put into a power save mode to a reduction power when notselected for communications. An embodiment power save mode may includereduction in the frequency of CPU clocks, logic block clocks, and/orsystem clocks. In some embodiments, CPU power intensive functions suchas compression are disabled or not used to save power when a trafficcontroller determines they are not necessary to meet the trafficrequirements and channel conditions. Using lower orders of modulationalso allows for the use of lower clock rates.

In an embodiment, different devices in the network that support thetraffic requirements are selected based on each device's network powerrating metric. This power rating metric may be assigned as a single orplurality of metrics and stored digitally in the device, and may bemeasured by a power measuring device that reports results to the deviceor is otherwise accessible by the network to make its metrics availableto a hybrid network controller. In some embodiments, power is reduced byscheduling traffic in time or in packet sequence. Bursting, buffering,signal level, modulation methods and density, FEC techniques, and mediaaccess mechanisms may be selected to adjust power. Information based onqueue statistics, traffic type, QoS requirements, applicationinformation, channel history, etc. may be used to determine selectednetwork parameters that affect power consumption. In one embodiment,data is routed per data stream or per packet in response to the traffictype, channel conditions, network congestion. In another embodiment, thenetwork protocol may increase or decrease the CSMA contention windows orStayout region, (allocated time slots) to further reduce the energyrequired to use the network. Using such a method, the network controllermay effectively reduce power consumption across every device in thenetwork.

In an embodiment, multiple networks may be linked though a plurality ofCDHN devices, where CDHN devices may perform either a simple packetforwarding or more sophisticated functions such as IP routing or evenmulti-protocol translation. Each link may be a “hop”, wherein eachdevice sends the source CDHN controller, the relevant power consumptiondata and the source CDHN controller (or another device/node tasked withsuch a decision making) decides which path and power management methodsare appropriate to use, and routes traffic accordingly. Multiplenetworks may be linked though a plurality of CDHN devices, each linkbeing a “hop”, wherein each device can share relevant power consumptiondata (metrics) with devices on either side so it can decide, itself,which path and power management means are appropriate to use the minimumenergy. In some embodiments, systems and methods described in U.S.Patent Publication No. 2005/0043858 entitled, “Atomic Self-HealingArchitecture,” which publication is incorporated herein by reference inits entirety, may be applied.

In an embodiment centralized approach, the controller is most likely tobe associated with the CCo-like function in IEEE 1901. In this case,information related to the overall system bandwidth requirements isavailable to the controller to make such decisions. An embodimentdecentralized approach would fit the networks if a central coordinatingfunction does not exist or is not desirable. In this case, a networkingnode may monitor the network loading level and make decisions related tothe transmit power reduction for a specific link based on the historical(recent or analyzed over extended periods of time) network loading, thetrend of the network loading (increase or decrease in loading), and theloading of the local TX queues. In an embodiment, the algorithm providesfor the constant network loading monitoring so in the case of theincreased congestion the TX power may be raised to increase the linkperformance. In an embodiment, power consumption analysis is to beassociated with the traffic type and either a node or the whole systemcan “learn” how to associate power consumption patterns with certaintraffic types (VoIP, Video Streaming, bursty downloads, etc.) and applypower management schemas either stored in the memory of a device or asystem, or develop the best suitable power management schema learningthe traffic pattern and apply such schema next time when the same typeof traffic is detected. Such a learning mechanism may also include theability to improve itself with each operation cycle. For example, in oneembodiment a hybrid network controller may associate power consumptionpatterns with traffic types, and apply a power management schema to theassociated traffic type. The hybrid network controller may associatepower consumption patterns by logging monitored traffic types andmeasured power consumption data corresponding to the monitored traffictypes.

In an embodiment, network behavior is used as an input to a power andsystem management controller. By introducing power consumption metricsto a path selection algorithm, power consumption of the hybrid networkmay be reduced. This type of power consumption optimization by selectingvarious data paths, and by selecting various power down and powersavings options, can be applied to a number of different types ofnetworks.

For example, embodiments of the present invention may be applied towarda network based on a single media type and a hybrid network that isbased on two or more media types. One example of a single media typenetwork is an IEEE 1901 power line network, while an example of amultiple media network, is a network that includes IEEE 1901, IEEE802.11x, and/or other network types as discussed above. In someembodiments, power consumption is predicted on a device level. Thisprediction may be based on the content of data queues, QoS parametersand network behavior. In some embodiments, historical metrics, forexample, network usage statistics, may be used to determine and predictpower consumption, and help determine appropriate path selectionalgorithms and power-down parameters. On the device level, historicalinformation about how the device itself is used may also be considered.

With respect to single media type (single path) network, such as an IEEE1901 network, device and system power consumption may be optimized bychanging data scheduling, bursting buffering and other types of networkbehaviors. With respect to multipath hybrid networks, data pathselection and device power parameters may be performed on both thedevice level, as stated above, and by changing data scheduling, burstingbuffering and other types of network behaviors as in the case of thesingle path network.

Power consumption may be optimized for a particular datalink and/orapplication. This optimization may be based on a QoS driven slotassignment or bandwidth reservation, using heartbeat techniques, orother methods. In some embodiments, these methods allow traffic to bescheduled so the times when the relevant interfaces and components needto be active are predictable. Heartbeat techniques may also be used toindicate which the parts of a system have gone to sleep or are notavailable. In one embodiment, for example, in the case of a multi-hopdata connection, power per hop is also included as an input in theembodiment power optimization algorithms. Embodiment power optimizationsalgorithms may also determine how much power is reduced if differentorders of modulation are used. Peripherals may also be disabled. Forexample, if an embodiment power optimization algorithm determines thatone technology end point/network interface is sufficient to deliver arequisite amount of data at a requisite QoS, other interfaces and/orperipherals may be shut down and/or disabled in order to allow thehybrid network to operate at a lower power. In an embodiment, aninterface between a physical layer and media access layer embodiment anda system to which they are attached allows the system to receive fromPHY/MAC the information related to the “power cost” of the transmissionand such other parameters as an example required time to “wake up” ortransition from “STAND BY” to “IDLE” or “ACTIVE” states. This sameinterface may further allow for the system to configure power managementoption and/or patterns.

In one example of a preferred embodiment a system may be composed insuch way that each media specific PHY/MAC is capable of providing acentralized controller with the information that contains power cost perunit of information transmitted and received, time required for thespecific PHY/MAC to transition from “IDLE” to “ACTIVE” and furthermorefrom “Receive” to “Transmit” and vice versa. At the same time thecentralized controller may be also responsible for the scheduling of thetraffic. In this case the system may also select a mode of operationwhere a transmission of a video stream is done via Media A, while thereceive operation associated with infrequent status updated informationfrom the receiving node is done over Media B, additionally the PHY/MACassociated with Media B is transitioning from “IDLE” to “Receive” andback to “IDLE” based on the scheduled operation.

In some embodiments, the power consumption of the various components ofthe hybrid network system may be determined in the laboratoryenvironment and power profiles are assigned based on the measuredperformance. In some embodiments, each network device may even assignthemselves power metrics. When measuring the power in the lab, a livemeasurement may be performed near power distribution, in order todetermine system level power consumption. In one embodiment, the powerconsumed by the system as measured at the energy supply is measured andcompared with the energy consumption measured by the interfaces so thatan accurate metric of system energy consumption required for eachnetwork is assessed. In some embodiments, queue, content, scheduling,types, volume, etc. are used to control power consumption. Combinationsof power saving methods may also be used.

In an embodiment, depending on different amount of power used byhardware or the CPU, it may be determined whether to use burst operation(perform all the processes at once), continual operation (performprocess but share time with other CPU or hardware processes), or whetherto use functions that consume lots of CPU cycles such as compression.

In some embodiments of the present invention, transmit power may bebased on the throughput requirements and available SNR. For example, ifthe link offers a high SNR that affords a very high throughput, but theonly traffic that needs to be transmitted on this link is a relativelylow bitrate audio, then shorter preambles and/or lower transmit powermay be used in order to reduce power consumption while providing therequired throughput. Feedback mechanisms may also be used. Furthermore,transmit power may be reduced based on QoS requirements and overallnetwork loading to avoid artificially created network congestion as anexample.

In one embodiment, a channel estimation process may be extended toinclude a function that negotiates not only the source (transmitter)transmit power, but also the receiver's transmit and response powerlevel if the protocol requires the receiver to provide acknowledgmentsor any other type of response to the transmitter. For example, atransmitted power field may be added to a channel estimation request. Inthe intermediate channel estimation responses, the receiver may indicatehow the transmitter should modify the transmit power level. For example,the receiver may request a particular increase in transmit power. Insome embodiments it is ensured that the receiver can hear thetransmitter channel estimation request. In some embodiments, ready tosend/clear to send (RTS/CTS) frame controls may be used at maximumtransmit power during negotiation. Such an embodiment example may beused to determine back-channel signal amplitude for responses. In someembodiments, the controller or receiving devices extrapolates tone mapsthat would be optimized for maximum energy efficiency for a given volumeof traffic, for example from high traffic volume/high bandwidth to lowtraffic volume/low bandwidth. Using sets of maps for specific levels ofperformance reduces the energy required to transmit multiple dynamictone maps.

In an embodiment, an optimum transmitter power is computed based on thechannel estimation responses without burdening the receiver with theneed to provide additional information. This technique may be applied,for example, in cases where an embodiment system is operating on anetwork that is comprised in part of older devices not equipped withthis functionality.

In some embodiments, power optimization may be performed on theaggregate signal level or on each carrier (in the multi-carrier or OFDMsystem) individually. In the case of the per-carrier adjustment, wellperforming carriers may be used while shutting down carriers with poorperformance. It is likely that carriers exhibiting low performance wouldbe associated with the lower impedance of the network as seen bytransmitter. This may help with the additional reduction of power whileimproving the linearity of the transmit path drivers/amplifiers. In someembodiments, systems and method described in U.S. Patent Publication No.2003/0071721 entitled, “Adaptive Radiated Emission Control,” whichpublication is incorporated herein by reference in its entirety, may beapplied.

In one embodiment, the transmitting node may be the same method toperform the channel estimation, but after the computation of the tonemap was accomplished at the full TX power, a new request is generatedafter the TX power is adjusted by the TX node to maintain enough SNR(overall or per carrier) to provide sufficient throughput.

In one embodiment, early preamble symbols may be detected at a dividedclock rate in order to save power. In some embodiments, these preamblesymbols may not need phase measurements or precise demarcation.

In an embodiment, the network device or interface may use energy from amore energy efficient source. For example, AC power may be taken from aPLC network interface connected to AC mains or a DC circuit. Ethernetnetworks may be carrying DC power over Ethernet and be more efficient orconvenient for devices to use, especially if power to a device is cutoff.

In some embodiments, the power may be accumulated from receivedtransmissions. For example, some of the transmit energy may be harvestedfrom the received signal for use in subsequent transmissions, or from apower supply at the lower current. Furthermore, a software levelunderstanding of the network state may be used to enable or disableportions of the network hardware. One embodiment approach is harvestingthe energy from the receive signal to perform “wake on LAN” functions atsignificantly reduced power consumption while other components of thesystem including the AC/DC or DC/DC power supplies are either in standbyor power down mode.

In some embodiments, the frequency ranges used for transmissions may bemanaged with respect to transmissions different destinations based onparameters such as the SNR. For example, communications may be performedusing fewer IEEE 1901-based carriers. Alternatively, the number oftransmit carriers may be reduced in other systems in order to savepower. In some embodiments, transmissions may be looped back to thesource, thereby allowing the source to measure the energy it's actuallyoutputting on different portions of the transmit spectrum. In someembodiments, this loop back transmission scheme is performed using anattenuator. The information obtained from loopback transmissions may begiven to data recipients, such that actual signal degradation alongdifferent frequencies may be measured rather than inferring the level ofsignal degradation based on an assumption of a perfect transmitter. Inone embodiment the system or a node may learn how to transmit in fewercarriers that are grouped in a contiguous frequency band and reduceclocking speed requirements for the transmitting and receiving nodesoperating in this mode.

In some embodiments, aspect oriented programming (AOP) may be used inthe software code that controls the hybrid network adapter in order tocentralize power management decisions while making sure that there is nointerference with the composition of the rest of the system. In anembodiment, using a message passing software architecture, powermanagement code may be allowed to intercept messages between differentcomponents of the system. The power management code then maintains aninternal model of how the system will behave. This internal model may beused to enable, disable, and adjust voltages, clocks, and otherparameters of different hardware components according to whether thehardware components are required according to the particular powerconsumption state of the system and/or operational decisions made bysuch management code. In some embodiments, the hybrid adapter has theability to learn the network topology along its associated powerconsumption.

In some embodiments, a determination is made on whether to use per flowor per packet routing. For example, in a network with plenty ofbandwidth available, per packet routing may be selected when congestionis encountered. In some embodiments, per flow routing may be lesscomputationally intensive then per packet routing. In some embodiments,throttle clocks may be used to minimize power consumption.

In some embodiments, power may be controlled by enabling or disablingparticular underlying interfaces within the network adapter system,depending on bandwidth requirements and device coverage. For example, ifthere are only two devices that may connect over a particular network,for example a Wi-Fi device or a MoCA device, the lowest power connectionfor the communications may be the only one used until it can no longermeet its bandwidth requirements.

In one embodiment, a hybrid network may have a device for discoveringhow much marginal power would be dissipated by establishing a trafficpattern along a network path, and by transmitting a given trafficpattern along the path. For example, the power dissipated byestablishing the traffic pattern would be the power dissipated by thepower takes to enable particular network interfaces. In one example, apath proceeds from an IEEE 1901 device interface (STA1), to an IEEE 1901interface in a second device (STA2), to an Ethernet device in the seconddevice (STA2 ETH), to an Ethernet interface in a third device (STA ETH)to the third device (STA3). This particular path or setup sequence maybe represented as: STA1 IEEE 1901→STA2 IEEE 1901→STA2 ETH→STA3 Eth→STA3.It should be understood that this particular path is just one specificembodiment example of a particular path, as other embodiment paths usingother combinations of devices and interface types may be implemented. Insome embodiments, clock scaling may be managed based on knowledgerelated to traffic requirements and bandwidth reservation andscheduling. In some embodiments, the power dissipated by the setupsequence may be determined using various combinations of paths andpatterns, measuring the power consumption changed by the network, andreporting this power consumption change back to the controller.

In accordance with an embodiment, a network device includes a first datainterface, a hybrid network controller coupled to the first datainterface, and a plurality of network interfaces coupled to the hybridnetwork controller. The plurality of network interfaces include at leastone media access control (MAC) device configured to be coupled to aplurality of physical layer interfaces (PHYs). The hybrid networkcontroller is configured to determine a network path comprising at leastone of the plurality of network interfaces that has a lowest powerconsumption of available media types coupled to the plurality of PHYs,and determine over which of the plurality of network interfaces thefirst data interface sends data to and receives data from, based on thedetermined network path. The network path may be dynamically determinedduring operation of the hybrid network controller, and/or the networkpath may be dynamically determined on a per packet basis or on a perpacket segment basis.

In an embodiment, an interface between a physical layer and a mediaaccess layer is configured to receive a power cost metric of atransmission from the MAC device or from one of the plurality of PHYs.The hybrid network controller may be further configured to reduce anoutput power of at least one PHY based on channel conditions seen by atleast one of the plurality of network interfaces. The controller mayreduce an output power of the at least one PHY by reducing a number oftransmitted carriers grouped in a contiguous frequency band in a reducedcarrier mode and/or by reducing clocking speed requirements fortransmitting and receiving node when operating in the reduced carriermode.

The hybrid network controller may be further configured to determine alowest power consumption of available media types based on parametersincluding automatic gain control (AGC) setting, signal to noise ratio(SNR) of the available media types, and quality of service (QoS)parameters of transmitted data. In some cases, the QoS parameterscomprise a priority parameter. The hybrid network controller may also befurther configured to reduce an output power of a network interface ofthe plurality of network interfaces by powering down the networkinterface or placing the network interface in a power saving mode whenthe network interface is not selected for communication. In someembodiments, the hybrid network controller is configured to place thenetwork interface in the power saving mode by reducing a frequency of aCPU clock or a system clock.

The hybrid network controller may be configured to reduce a power of thePHY or the MAC by disabling data compression and encryption when atraffic controller determines that data compression and encryption arenot necessary based on traffic requirements channel conditions. In someembodiments, the hybrid network controller may include the trafficcontroller.

In an embodiment, the hybrid network controller determines the networkpath based on a power rating metric of the network device. The powerrating metric of the network device may be digitally stored on thedevice as a single power rating metric or as a plurality of power ratingmetrics. The network device may further include a power measuringsub-system configured to measure the power rating metric and report thepower rating metric to hybrid network controller. The power measuringdevice may be further configured to make the power rating metricavailable to a traffic controller and to a network coupled to thenetwork device.

In an embodiment, the hybrid network controller is further configured toreduce power consumption of the network device by scheduling traffic intime on in a packet sequence using bursting, buffering, modulationcomplexity, preamble methods, or using information based on queuestatistics, traffic type, application information or channel history.The hybrid network controller may be further configured to route dataper data stream or per packet in response to a traffic type, channelconditions, and a measure of traffic congestion.

In an embodiment, the hybrid network controller is further configured toassociate power consumption patterns with traffic types. For example,the hybrid network controller may be further configured to apply a powermanagement schema to the associated traffic type. The hybrid networkcontroller may further associate power consumption patterns by loggingmonitored traffic types and measured power consumption datacorresponding to the monitored traffic types.

In accordance with a further embodiment, a network device includes anetwork controller and at least one network interface coupled to thenetwork controller that includes at least one media access control (MAC)device configured to be coupled to at least one physical layer interface(PHY). The network controller may be configured to determine a networkpath comprising the at least one network interface that has a lowestpower consumption of available media types coupled to the at least onePHY. In some embodiments, the network controller may be a hybrid networkcontroller.

In some embodiments, the network controller is further configured todetermine the network path by receiving power consumption data fromfurther network devices, selecting a plurality of the further networkdevices based on the received power consumption data, and routing dataon the selected plurality of further network devices. The networkcontroller may be further configured to determine a data path of theselected plurality of further network devices, and determine path andpower management methods for at least one of the selected plurality offurther network devices.

In some embodiments, the network controller is further configured totransmit power consumption data to a first further network device,receive a data path assignment from the further network device based onthe transmitted power consumption data, and relay data from the furthernetwork device to a second further network device based on the pathassignment. The network controller may also be configured to receive arequested path and power management method from the first furthernetwork device, and relay the data from the further network device tothe second further network device based further on the received path andpower management method.

In some embodiments, the network controller is configured to determine apower management method, and relay the data from the further networkdevice to the second further network device based further on thedetermined path and power management method.

In accordance with a further embodiment, method of operating a networkdevice includes determining a network path comprising at least one of aplurality of network interfaces that has a lowest power consumption ofavailable media types, and determining over which of the plurality ofnetwork interfaces the first data interface sends data to and receivesdata from, based on the determined network path. Determining the networkpath may be dynamically performed during operation of the networkdevice.

In some embodiments, the method also includes reducing an output powerof at least one physical layer interface (PHY) based on channelconditions seen by at least one of the plurality of network interfaces.The method may also include determining a lowest power consumption ofavailable media types based on parameters including automatic gaincontrol (AGC) setting, signal to noise ratio (SNR) of the availablemedia types, and quality of service (QoS) parameters of the availablemedia types.

In an embodiment, the method further includes reducing an output powerof a network interface of the plurality of network interfaces, reducingcomprising by powering down the network interface or placing the networkinterface in a power saving mode when the network interface is notselected for communication. Placing the network interface in the powersaving mode may include reducing a frequency of a CPU clock or a systemclock.

In an embodiment, the method further includes determining that datacompression and encryption are not necessary based on trafficrequirements channel conditions, and reducing a power consumed by thenetwork device by disabling data compression based on determining thatdata compression and encryption are not necessary. The method mayfurther include determining that data compression and encryption may berelaxed based on traffic requirements channel conditions, and reducing apower consumed by the network device by reducing a complexity of forwarderror correction (FEC) disabling data compression based on determiningthat data compression and encryption may be relaxed.

In an embodiment, the method may further include determining a powerrating metric of the network device, wherein determining the networkpath is performed based on the determined power rating metric.Determining the power rating metric may include performing a powermeasurement, and the power metric rating may be defined as a powerconsumed per unit of transmitted or received information. The method mayfurther include reporting the power rating metric to a further networkdevice coupled to the network device.

In an embodiment, the method further includes reducing power consumptionof the network device by scheduling traffic in time on in a packetsequence, using bursting, buffering, modulation complexity, preamblemethods, or using information based on queue statistics, traffic type,application information or channel history. The method may also includerouting data per data stream or per packet in response to a traffictype, channel conditions, and a measure of traffic congestion.

In accordance with a further embodiment, a network device includes ahybrid network controller, and a plurality of network interfaces coupledto the hybrid network controller. Each of the plurality of networkinterfaces may be configured to be coupled to a corresponding physicallayer interface (PHY). The network device also includes a processingengine configured to perform MAC functions common to the plurality ofnetwork interfaces. The hybrid network controller may be furtherconfigured to determine a network path comprising at least one networkinterface that has a lowest power consumption of available media typescoupled to the plurality of PHYs. In some embodiments, the MAC functionscomprise queuing functions for the plurality of network interfaces.

In accordance with a further embodiment, a network device includes aplurality of network interfaces coupled to a hybrid network controller.Each of the plurality of network interfaces may be configured to becoupled to a corresponding physical media via a corresponding physicallayer interface (PHY). The network device also includes a processingengine configured to perform MAC functions common to the plurality ofnetwork interfaces and a hybrid network controller function. The hybridnetwork controller may be configured to determine a network path thatincludes at least one network interface of the plurality of networkinterfaces having parameters that decrease power consumption. In someembodiments, the hybrid network controller is further configured todetermine a network path that meets a Quality of Service (QoS)requirement. In some embodiments, the hybrid network controller isconfigured to determine a network path comprising at least one networkinterface of the plurality of network interfaces having the parametersthat best meet Quality of Service and power consumption requirements. Aswith other embodiments, MAC functions may include queuing functions forthe plurality of network interfaces and a network convergence layer.

Advantages of embodiment systems include the ability to reduce energy,cost of ownership and improve the system design by using embodimentsystems, methods and combinations of systems and method described hereinto optimize energy consumption.

Another advantage of embodiment systems includes the ability to improvepower efficiency while maintaining traditional QoS metrics. Furtheradvantages include, the ability to reduce the range in which it ispractical to eavesdrop on a communications link, the ability to decreaseinterference between radio networks; and the ability to decrease thedemand placed on the power distribution infrastructure.

The following U.S. Patent Application Publications and U.S. Patents areincorporated herein by reference in their entirety: U.S. PatentPublication No. 2003/0071721, entitled “Adaptive radiated emissioncontrol;” U.S. Patent Publication No. 2005/0043858, entitled “Atomicself-healing architecture;” U.S. Patent Publication No. 2008/0205534,entitled “Method and system of channel analysis and carrier selection inOFDM and multi-carrier systems;” U.S. Pat. No. 6,891,796, entitled,“Transmitting data in a power line network using link qualityassessment;” U.S. Pat. No. 6,917,888, entitled, “Method and system forpower line network fault detection and quality monitoring;” U.S. Pat.No. 7,106,177, entitled, “Method and system for modifying modulation ofpower line communications signals for maximizing data throughput rate;”U.S. Pat. No. 7,193,506, entitled, “Method and system for maximizingdata throughput rate in a power line communications system by modifyingpayload symbol length;” U.S. Pat. No. 7,245,625, entitled,“Network-to-network adaptor for power line communications;” and U.S.Pat. No. 7,286,812, entitled, “Coupling between power line and customerin power line communication system.” Systems and methods described inthe above mentioned U.S. Patents and U.S. Patent Applications can beapplied to embodiments described herein.

The following standards document is incorporated by reference herein inits entirety: IEEE Std 1901-2010™—IEEE Standard for Broadband over PowerLine Networks: Medium Access Control and Physical Layer Specifications,New York, N.Y.: IEEE.

It will also be readily understood by those skilled in the art thatmaterials and methods may be varied while remaining within the scope ofthe present invention. It is also appreciated that the present inventionprovides many applicable inventive concepts other than the specificcontexts used to illustrate embodiments. Accordingly, the appendedclaims are intended to include within their scope such processes,machines, manufacture, compositions of matter, means, methods, or steps.

What is claimed is:
 1. A network device comprising: a networkcontroller; and at least one network interface coupled to the networkcontroller, the at least one network interface comprising at least onemedia access control (MAC) device configured to be coupled to at leastone physical layer interface (PHY), wherein: the network controller isconfigured to determine a network path comprising at least one networkinterface that has a lowest power consumption of available media typescoupled to the at least one PHY.
 2. The network device of claim 1,wherein the network controller is further configured to determine thenetwork path by receiving power consumption data from further networkdevices, selecting a plurality of the further network devices based onthe received power consumption data, and routing data on the selectedplurality of further network devices.
 3. The network device of claim 2,wherein the network controller is further configured to determine a datapath of the selected plurality of further network devices, and determinepath and power management methods for at least one of the selectedplurality of further network devices.
 4. The network device of claim 1,wherein the network controller is further configured to transmit powerconsumption data to a first further network device, receive a data pathassignment from the further network device based on the transmittedpower consumption data, and relay data from the further network deviceto a second further network device based on the path assignment.
 5. Thenetwork device of claim 4, wherein the network controller is configuredto receive a requested path and power management method from the firstfurther network device, and relay the data from the further networkdevice to the second further network device based further on thereceived path and power management method.
 6. The network device ofclaim 4, wherein the network controller is configured to determine apower management method, and relay the data from the further networkdevice to the second further network device based further on thedetermined path and power management method.
 7. The network device ofclaim 1, wherein the network controller is a hybrid network controller.8. A network device comprising: a first data interface; a hybrid networkcontroller coupled to the first data interface; and a plurality ofnetwork interfaces coupled to the hybrid network controller, theplurality of network interfaces comprising at least one media accesscontrol (MAC) device configured to be coupled to a plurality of physicallayer interfaces (PHYs), wherein the hybrid network controller isconfigured to determine a network path comprising at least one of theplurality of network interfaces that has a lowest power consumption ofavailable media types coupled to the plurality of PHYs, and determineover which of the plurality of network interfaces the first datainterface sends data to and receives data from, based on the determinednetwork path.
 9. The network device of claim 8, wherein the network pathis dynamically determined during operation of the hybrid networkcontroller.
 10. The network device of claim 9, wherein the network pathis dynamically determined on a per packet basis or on a per packetsegment basis.
 11. The network device of claim 8, wherein: an interfacebetween a physical layer and a media access layer is configured toreceive a power cost metric of a transmission from the MAC device orfrom one of the plurality of PHYs.
 12. The network device of claim 8,wherein the hybrid network controller is further configured to reduce anoutput power of at least one PHY based on channel conditions seen by atleast one of the plurality of network interfaces.
 13. The network deviceof claim 12, wherein the controller reduces an output power of the atleast one PHY by reducing a number of transmitted carriers grouped in acontiguous frequency band in a reduced carrier mode.
 14. The networkdevice of claim 13, wherein the controller further reduces clockingspeed requirements for transmitting and receiving node when operating inthe reduced carrier mode.
 15. The network device of claim 8, whereinhybrid network controller is further configured to determine a lowestpower consumption of available media types based on parameters includingautomatic gain control (AGC) setting, signal to noise ratio (SNR) of theavailable media types, and quality of service (QoS) parameters oftransmitted data.
 16. The network device of claim 15, wherein the QoSparameters comprise a priority parameter.
 17. The network device ofclaim 8, wherein the hybrid network controller is further configured toreduce an output power of a network interface of the plurality ofnetwork interfaces by powering down the network interface or placing thenetwork interface in a power saving mode when the network interface isnot selected for communication.
 18. The network device of claim 17,wherein the hybrid network controller is configured to place the networkinterface in the power saving mode by reducing a frequency of a CPUclock or a system clock.
 19. The network device of claim 8, wherein thehybrid network controller is configured to reduce a power of the PHY orthe MAC by disabling data compression and encryption when a trafficcontroller determines that data compression and encryption are notnecessary based on traffic requirements channel conditions.
 20. Thenetwork device of claim 19, wherein the hybrid network controllercomprises the traffic controller.
 21. The network device of claim 8,wherein the hybrid network controller determines the network path basedon a power rating metric of the network device.
 22. The network deviceof claim 21, wherein the power rating metric of the network device isdigitally stored on the device as a single power rating metric or as aplurality of power rating metrics.
 23. The network device of claim 21,further comprising a power measuring sub-system configured to: measurethe power rating metric; and report the power rating metric to hybridnetwork controller.
 24. The network device of claim 23, wherein thepower measuring device is further configured to make the power ratingmetric available to a traffic controller and to a network coupled to thenetwork device.
 25. The network device of claim 8, wherein the hybridnetwork controller is further configured to reduce power consumption ofthe network device by scheduling traffic in time on in a packetsequence, using bursting, buffering, modulation complexity, preamblemethods, or using information based on queue statistics, traffic type,application information or channel history.
 26. The network device ofclaim 25, wherein the hybrid network controller is further configured toroute data per data stream or per packet in response to a traffic type,channel conditions, and a measure of traffic congestion.
 27. The networkdevice of claim 8, wherein the hybrid network controller is furtherconfigured to associate power consumption patterns with traffic types.28. The network device of claim 27 wherein the hybrid network controlleris further configured to apply a power management schema to theassociated traffic type.
 29. The network device of claim 27, wherein thehybrid network controller associates power consumption patterns bylogging monitored traffic types and measured power consumption datacorresponding to the monitored traffic types.
 30. A method of operatinga network device comprising a first data interface and a plurality ofnetwork interfaces, the method comprising: determining a network pathcomprising at least one of the plurality of network interfaces that hasa lowest power consumption of available media types; and determiningover which of the plurality of network interfaces the first datainterface sends data to and receives data from, based on the determinednetwork path.
 31. The method of claim 30, wherein determining thenetwork path is dynamically performed during operation of the networkdevice.
 32. The method of claim 30, further comprising reducing anoutput power of at least one physical layer interface (PHY) based onchannel conditions seen by at least one of the plurality of networkinterfaces.
 33. The method of claim 30, further comprising determining alowest power consumption of available media types based on parametersincluding automatic gain control (AGC) setting, signal to noise ratio(SNR) of the available media types, and quality of service (QoS)parameters of the available media types.
 34. The method of claim 30,further comprising reducing an output power of a network interface ofthe plurality of network interfaces, reducing comprising by poweringdown the network interface or placing the network interface in a powersaving mode when the network interface is not selected forcommunication.
 35. The method of claim 34, wherein placing the networkinterface in the power saving mode comprises reducing a frequency of aCPU clock or a system clock.
 36. The method of claim 30, furthercomprising: determining that data compression and encryption are notnecessary based on traffic requirements channel conditions; and reducinga power consumed by the network device by disabling data compressionbased on determining that data compression and encryption are notnecessary.
 37. The method claim 30, further comprising: determining thatdata compression and encryption may be relaxed based on trafficrequirements channel conditions; and reducing a power consumed by thenetwork device by reducing a complexity of forward error correction(FEC) disabling data compression based on determining that datacompression and encryption may be relaxed.
 38. The method of claim 30,further comprising: determining a power rating metric of the networkdevice, wherein determining the network path is performed based on thedetermined power rating metric.
 39. The method of claim 38, whereindetermining the power rating metric comprises performing a powermeasurement.
 40. The method of claim 38, wherein the power metric ratingcomprises a power consumed per unit of transmitted or receivedinformation.
 41. The method of claim 38, further comprising reportingthe power rating metric to a further network device coupled to thenetwork device.
 42. The method of claim 30, further comprising reducingpower consumption of the network device by scheduling traffic in time onin a packet sequence, using bursting, buffering, modulation complexity,preamble methods, or using information based on queue statistics,traffic type, application information or channel history.
 43. The methodof claim 30, further comprising, routing data per data stream or perpacket in response to a traffic type, channel conditions, and a measureof traffic congestion.
 44. A network device comprising: a plurality ofnetwork interfaces coupled to a hybrid network controller, each of theplurality of network interfaces configured to be coupled to acorresponding physical media via a corresponding physical layerinterface (PHY); a processing engine configured to perform MAC functionscommon to the plurality of network interfaces and a hybrid networkcontroller function, wherein the hybrid network controller is configuredto determine a network path comprising at least one network interface ofthe plurality of network interfaces having parameters that decreasepower consumption.
 45. The network device of claim 44, wherein thehybrid network controller is further configured to determine a networkpath that meets a Quality of Service (QoS) requirement.
 46. The networkdevice of claim 44, wherein the MAC functions comprise queuing functionsfor the plurality of network interfaces and a network convergence layer.